Issue – No sounds after upgrading iPhone from iOS 6 to iOS 7
I lost all sound alerts after upgrading from iOS 6 to iOS 7 on an iPhone 5. Music and phone audio worked fine but I had no alert or notification sounds for email, messages, calendar or voicemails. Adjusting volume or making changes via Settings > Sounds or Settings > Notification Center had no affect. Turning Settings > Sounds > Change with Buttons on or off had no affect. When choosing a new sound for text or email I could just barely hear it, as if it were far far away in another room – but only if I was in a completely silent setting. Weird.
Solution – Settings > General > Reset All Settings
Takes about a minute and immediately restored Sound notifications for all features of the phone. You wont lose any apps or data but device settings will be reset to defaults: Sounds, Notifications, Wallpaper, Home screen, WiFi connections, Auto-lock time, Location Services etc. Perform a backup before resetting and backup any photos or music just to be safe.